Since ethanol is cheaper than gasoline , today's gasoline's contain varying amonts of ethanol to keep prices lower. given that the enthalpy of combustion of ethanol is -1367 kj/mole and that the aveage energy released by one gram of gasoline is 43 kj:
) Calculae the heat released by on Gram of ethanol.
Please Give as much detail as possible instructor will not help cause I missed this lecture because of a family emergency !! please
1367 kJ/mol for 1 mole C2H5OH (1 mol = 46 grams) which is the same as 1367 kJ/46 grams. So 1 g will release
1367 kJ x (1g/46g) = ?
I assume the 43 kJ for 1 g gasoline is there to confuse you (unless the idea is to give you a number to compare).
Thanks The 43kjwas really confusing
To calculate the heat released by one gram of ethanol, we need to use the enthalpy of combustion of ethanol. The enthalpy of combustion is the amount of heat released when a substance undergoes complete combustion.
Given that the enthalpy of combustion of ethanol is -1367 kJ/mole, we need to convert this value to kJ/gram since we are interested in calculating the heat released by one gram of ethanol.
To convert from moles to grams, we need to know the molar mass of ethanol. The molar mass of ethanol can be calculated by adding up the atomic masses of its constituent elements: carbon, hydrogen, and oxygen.
The atomic mass of carbon (C) is approximately 12.01 g/mol, hydrogen (H) is approximately 1.008 g/mol, and oxygen (O) is approximately 16.00 g/mol.
The molecular formula of ethanol is C2H5OH, so we have:
2 moles of carbon (2 × 12.01 g/mol)
6 moles of hydrogen (6 × 1.008 g/mol)
1 mole of oxygen (1 × 16.00 g/mol)
Total molar mass of ethanol = (2 × 12.01) + (6 × 1.008) + 16.00 = 46.08 g/mol
Now we can calculate the enthalpy of combustion per gram of ethanol by dividing the enthalpy of combustion by the molar mass:
Enthalpy of combustion per gram of ethanol = (-1367 kJ/mole) / (46.08 g/mol)
Now, we can calculate the heat released by one gram of ethanol by multiplying the enthalpy of combustion per gram by 1 gram of ethanol:
Heat released by one gram of ethanol = (enthalpy of combustion per gram) × (1 gram)
Substituting the values, we get:
Heat released by one gram of ethanol = (-1367 kJ/mole) / (46.08 g/mol) × 1 gram
Calculating this expression will give you the answer in kilojoules (kJ).